First, add the flour to a large mixing bowl. Make a well in the middle of the bowl then pour the yeast and sugar in the middle. Make sure to place the salt at one side away from the yeast.
Pour the water and olive oil into the middle of the well and using a wooden spoon or spatula mix everything together. Once the dough comes together tip it out onto a clean work surface lightly dusted with flour.
Knead the dough for 10 minutes until smooth and springy (press your finger lightly into the dough and if it springs back it's ready).
Clean and dry the mixing bowl then lightly coat it in olive oil. Place the ball of dough in the bowl and lightly rub the top of it with olive oil.
Cover with plastic wrap or cling film and place in a warm place for 1 hour or until doubled in size (not hot and not in direct sunlight).
Once the dough has doubled in size remove it and cut it in half. Place the dough in two separate oiled baking trays (I used 10x15inch) and spread it out to fit the trays. If you only want to make one then you can freeze the other half.
Let the dough rise in the trays for another hour or more.
Preheat the oven to 230C (450F) or your hottest setting. When ready to bake use your fingers to make dimples over the dough, sprinkle over fresh rosemary, sea salt flakes and olive oil.
Bake for 15-20 minutes until golden and baked through.